Animal and Plant Species in Antagonistic and Mutualistic Networks, a Multispecies Mean Field Model

We construct a dynamic system model of a web of NA?animal species interacting with NP plant species using a system of coupled differential equations. The model has a parameter which represents the effect of animal on plant species that can be positive (mutualistic interaction) or negative (antagonistic interaction). We work a Multispecies Mean Field Model MMFM in which the full set of NA and NP variables are reduced to a couple of an average animal and plant species. We study the conditions for existence of the MMFM and relate the result to the difference between animal and plant species in the network. We compare our results with empirical data from pollinators (mutualistic) and herbivorous insect (antagonistic) networks. We conclude by combining analytical and empirical work that antagonistic networks present fewer animal species in relation to plant species than mutualistic ones.

2015年巴西寨卡病毒感染与小头畸形之间可能存在的关联

2015年初,通过伊蚊传播的寨卡病毒在登革热病毒流行地区巴西的东北部暴发,该病毒属于黄病毒属。2015年9月,寨卡病毒流行地区开始出现关于小头畸形患儿的报道,且报道数量呈现增加的趋势。与此同时,有2名妇女产前超声检查发现有胎儿畸形,在她们的羊水中也检测出寨卡病毒RNA。